The Effect of Different Cooling Parameters on Fatigue Strength of 1040 Steel after Heat * Treatment
Abstract—In this study, fatigue strength and microstructural changes of AISI 1040 steel with different heat treatment parameters were investigated. 1040 steel is a material used in many areas today. Some of the material application areas can be subjected to cyclical loads. Fatigue strength, such as abrasion and tensile strength, is also very important in these materials. AISI 1040 steel can be easily heat- treated to increase strength. The samples were incubated at 920 ° C for 4 hours and controlled cooling in air, oil, water and oven. The microstructures of the samples after heat treatment were examined by optical microscope. Vickers hardness was performed for all samples. Force controlled fatigue test was performed. Broken surface images of fractured specimens were taken on Nikon ShuttlePix device during the test. The hardness of the water cooled sample was better than other heat treatment samples. It was observed that the increase in fatigue strength as a result of the hardness and pulling points increased.